The care information provided in this section represents the kind of practical advice is available for all the plants in this web site if you subscribe to the monthly customized newsletter Yardener’s Advisor.
Hypericums do not do well in dry soil. They particularly need watering when they are first planted and when rainfall is scarce during periods of drought. It is also a good idea to be sure they are well watered before the ground freezes for the winter. Water when the soil is dry and when there has been no rain for a week or so. Run a drip system or sprinkler for 20 minutes twice a week until regular rains resume. To minimize water loss, mulch hypericums.
For more information see file About Watering Equipment.
Feed hypericums in the fall. Sprinkle a handful or so of a granular general purpose fertilizer on the soil around each plant for the rain to water in. Do not allow it to get on the leaves or stems. A supplemental feeding during the long summer bloom season will boost the hypericum's vigor during the hottest days. Spray a dilute liquid fertilizer over all the leaves of the plant. This is not essential.
For more information see file About Fertilizers.
Hypericums benefit from a 2 or 3-inch layer of organic mulch over their roots all season long. Spread wood chips, chopped leaves, shredded bark or similar material on landscape fabric laid down first or directly on the soil around the base of each plant. This will help the soil retain moisture and minimize water waste from run-off and evaporation. It also discourages weeds. Keep the mulch about 6 inches away from the plant stems to avoid decay and rodent damage.
For more information see file on Using Mulch.
In warmer climates where hypericums winter over in tact, remove a third of the oldest branches in early spring. Cutting out these thicker, woodier stems will encourage vital, new stems to grow from the base of the plant. The shrub will soon regain its former size. In colder northern areas, hypericums often die back, their stems withering and turning brittle. Cut them all back to the ground in the spring to encourage new flowering shoots.
For more information see files on Pruning Shrubs and Choosing Pruning Tools.
A really cold winter will cause foliage to turn brown and even drop, but the plants usually recover easily. Protect hypericums in exposed sites from winter wind and snow with a burlap screen, evergreen boughs, and heavy mulch. Do not wrap shrubs with plastic that will cut off their air. For more information see the file Winter Protection For Plants and Plant Protection Supplies